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METHOdOLOGY IN EXPLOrING THE OXIdATION BEHAVIOr OF COATEd-CArBON CArBON COMPOSITES

JOUrNAL OF materials SCIENCE 1994年第5期29卷 1260-1264页

作者： WU, TM WU, Yr Materials R&D Center Chung Shan Institute of Science and Technology Lung-Tan Taiwan

The aim of this study was to develop a useful method of analysing the oxidation behaviour of coated-carbon/carbon (coated-C/C). A few experiments were needed to explore the oxidation rate of coated-C/Cs at various temperatures, and the activation energy of oxidation in each temperature interval was determined simultaneously. Combining theoretical analysis of the values of the activation energy and the temperature at which the mechanism changes, allows specification of the quality of the protective coating. The concept of the integrity of the coating layer is also explained from the theory of mass transportation. This analytical procedure offers a method of distinguishing the effectiveness of coated-C/Cs by different processes. The mechanism of oxidation at each temperature interval is also specified.

关键词： Carbon carbon composites

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HOT MACHINING PrOCESS FOr IMPrOVEd METAL rEMOVAL rATES IN TUrNING OPErATIONS

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JOUrNAL OF materials PrOCESSING technology 1994年第3-4期44卷 199-206页

作者： MAdHAVULU, G AHMEd, B Technology Development Laboratory Bharat Heavy Electricals Ltd. Corporate R&D Division Vikasnagar Hyderabad -500 593 India

This paper deals with the Hot Machining Process, for turning operations, which is designed to give improved metal removal rates, particularly on difficult-to-machine metals. A high temperature plasma arc is used to provide intense localised heat, softening only the chip material, leaving the work piece relatively cool and metallurgically undamaged. The advantages of plasma arc hot machining are increased metal removal rates, machining hard and tough metals, increase in tool life, suitable for interrupted cuts etc... This paper discusses the results of productivity studies and economic viabilities of the Hot Machining Process.

关键词： Machining

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PHOTOrEFrACTIVE EFFECT IN BI12SIO20 - Cr CrYSTALS AT 633NM

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APPLIEd PHYSICS LETTErS 1994年第10期65卷 1213-1215页

作者： YEH, TS LIN, WJ LIN, IN HU, LJ LIN, SP TU, SL LIN, CH HSU, SE Materials R&D Center Chung‐Shan Institute of Science and Technology P. O. Box 90008‐8‐6 Lung‐Tan Taiwan Republic of China

Pure and Cr2O3-doped Bi12SiO20 (BSO) single crystals have been successfully grown using Czochralski technique. doping 30 ppm of Cr2O3 into BSO single crystals has lowered the transmittance and increased the photochromic effect of the materials significantly. Although the overall diffraction efficiency of photorefractive effect in response to 633 nm laser beam has not been increased, the intrinsic diffraction efficiency (eta(i)) and the response time constant (tau) have been improved markedly. The applicability of the BSO crystals in the red light regime is thus increased.

关键词： Bismuth compounds

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robust control of an automatic transmission system for passenger vehicles

Robust control of an automatic transmission system for passe...

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IEEE Conference on Control technology and Applications (CCTA)

作者： Furukawa Hagiwara Fujita Uchida Tochigi R&d Center Honda Research and Development Company Limited Haga Tochigi Japan School of Information Science Japan Advanced Institute of Science and Technology Tatsunokuchi Ishikawa Japan Department of Electrical Engineering Waseda University Shinjuku Tokyo Japan

In recent years, electronic control of automatic transmissions, which provides an effective means of satisfying increasingly strict fuel efficiency requirements and improving drivability and shift quality, is applied to an increasing number of automobile models, and increasingly larger sections of automatic transmissions are electronically controlled. A new automatic transmission control theory which ensures high robustness and sufficient control performance has been developed through application of the H/sub /spl infin// control theory in order to make HONdA automatic transmissions more marketable. This paper reports that their control performance was favorable. This was verified by tests with actual vehicles, and the main processes to which it was applied.< >

关键词： robustness road vehicle control road vehicles H-infinity control

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Point defects in As‐grown and ion implanted GaAs probed by a monoenergetic positron beam

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AIP Conference Proceedings 1994年第1期303卷 92-100页

作者： A. Uedono S. Fujii L. Wei S. Tanigawa Research Center for Advanced Science and Technology University of Tokyo 4‐6‐1 Komaba Meguro‐ku Tokyo 153 Japan Opto‐electronics R&D Lab. Sumitomo Electric Industries Ltd. 1 Taya‐cho Sakae‐ku Yokohama 244 Japan Institute of Materials Science University of Tsukuba Tsukuba Ibaraki 305 Japan

defects in ion implanted GaAs were studied by monoenergetic positron beams. From measurements of doppler broadening profiles of the positron annihilation as a function of incident positron energy, it was found that a species of defects strongly depends on a species of implanted ions. Native defects in GaAs wafers were also studied. The present investigation shows that positrons provide a sensitive and nondestructive probe for the detection of both vacancies and interstitials.

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A new subunit of thermoelectric generator using single crystal‐like elements of laminated type

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AIP Conference Proceedings 1994年第1期316卷

作者： Y. Tanji Y. Nakagawa T. Kaneko H. Ido M. Kuboki M. Kogo T. Masumoto r. Sato R&D Division Tokin Corporation Sendai 982 Japan Faculty of Engineering Tohoku Institute of Technology Sendai 982 Japan Institute for Materials Research Tohoku University Sendai 980 Japan Faculty of Engineering Tohoku Gakuin University Tagajyo 985 Japan R&D Division Tokin Corporation Sendai 982 Japan Institute for Materials Research Tohoku University Sendai 980 Japan Faculty of Engineering Tohoku Gakuin University Tagajyo 985 Japan

A compact subunit of thermoelectric generator is designed using single crystal‐like 288 elements of (Bi,Sb)2 (Te,Se)3 compounds of laminated type. It is expected that the maximum power amounts to 17.3 (W) with 11.1 (A) and 1.56 (V) at the temperature difference of 50 °C. The elements are prepared by the Bridgman method using a new type of crucible. Thermoelectric properties of these elements are measured using a simple Peltier technique.

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HYBrId HYdrOFOIL technology APPLICATIONS

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NAVAL ENGINEErS JOUrNAL 1994年第1期106卷 123-136页

作者： MEYEr, Jr The Author:is manager of hydrofoil technology in the Hydrofoil Group of the Systems Department of the David Taylor Research Center. He holds bachelors and masters degrees in aeronautical engineering from Rensselaer Polytechnic Institute and has done additional graduate work at the Massachusetts Institute of Technology in the same field. Since joining the David Taylor Naval Ship R&D Center in 1971 he has been associated with advanced naval vehicles. Meyer has authored a number of DTRC reports AIAA and ASNE papers on the subject of hydrofoils and hybrid marine vehicles he holds several patents in this technical area. Prior to his current employment at DTRC Meyer held several research and development long-range planning and engineering management positions with Boeing-Vertol Trans-Sonics Inc. Air Force Cambridge Research Center and the Aero-Elastic Laboratory at MIT. Meyer has served on the AIAA Marine Systems and Technologies Committee the High Speed Vehicle Committee of the American Towing Tank Conference and now as president of the International Hydrofoil Society. He is a member of the American Society of Naval Engineers American Institute of Aeronautics and Astronautics and the Society of Sigma Xi.

The purpose of this paper is to provide a review of hybrid hydrofoil vehicle technology and feasibility designs, both military and commercial, that have been explored during the last several decades. A hybrid hydrofoil consists of a conventional monohull form with the addition of a long, slender, single strut and lower body added to its keel. The lower body buoyant lift is augmented by the dynamic lift from a fully-submerged foil system. Foil dynamic lift comes into play at speeds of about 12 to 15 knots and above, at which time the upper hull is lifted from the water surface leaving only the small waterplane of the single strut at the interface. The foil automatic control system maintains predetermined flying height and provides a stable platform in waves. The foil surfaces are sufficiently powerful to counter roll, pitch and heave motions that would be imparted to a conventional monohull in waves. Propulsion of a hybrid hydrofoil is provided by one or more prime movers in the upper hull, either driving through a mechanical Z-drive, or an electric transmission system, to one or more propellers on the stern of the lower hull. An alternate arrangement is to place the entire propulsion system in the lower hull, thereby eliminating a Z-drive requirement. The hybrid hydrofoil designs to be described will include USCG patrol craft, U.S. Navy long-range missile patrol craft, multi-mission deployable vehicle, multi-mission support vehicle, and small combatant, along with several commercial versions of the hybrid hydrofoil concept.

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MAKING PIPING SYSTEMS FIrE-SAFE - SIMPLE SOLUTIONS FOr PrEVENTING A dISASTEr

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NAVAL ENGINEErS JOUrNAL 1994年第3期106卷 285-295页

作者： BHASIN, V NILSEN, L GUPTA, K CONrOY, d Vinod Bhasin P.E.:is a fellow engineer with the Westinghouse Electric Corporation machinery technology division Pittsburgh Pa. He has more than 19 years of experience in the supervision design application and testing of valves and actuators and has taught courses in solids mechanics for 10 years at Illinois Institute of Technology Chicago Il. Mr. Bhasin has written articles for the valve industry where he has been active in standards societies. He holds BS and MS degrees in mechanical engineering and an MS in industrial engineering. Mr. Bhasin is a member of the American Society of Mechanical Engineers (ASME) and the American Society for Testing and Materials (ASTM). He is co-chairman of the shipbuilding piping component subcommittee ASTM F25.13 and is also chairing three other task groups under ASTM F25. Lloyd Nilsen P.E.:is the piping components branch head for NavSea. His career with NavSea includes 33 years of ship design construction and repair experience. He has held various positions in the power piping design division human factors manning and controls integration branch and submarine machinery systems branch. He has a BS degree in marine engineering from N.Y. State Maritime. Mr. Nilsen is also a member of the NavSea Association of Scientists and Engineers and a registered licensed professional engineer in Virginia and Washington D.C. Karan Gupta P.E.:is a senior engineer with the Westinghouse Electric Corporation Machinery Technology Division Pittsburgh Pa. Prior to joining Westinghouse he was employed by Elliott Company Jeannette Pa. for 12 years as a metallurgical engineer. He has more than 25 years experience in metallurgical engineering including material selection and brazing and welding of piping pressure vessels and turbines. Mr. Gupta has BS and MS degrees in metallurgical engineering. He is a member of the American Welding Society (AWS) and is active in AWS filler metal subcommittee A5A. He is also a member of ASM International. Dennis Conroy: is a chemical engineer

Loss of life and property losses totaling tens of billions of dollars have piping engineers scrambling to specify ''fire-safe'' components in fire-prone locations: on board ships, and in power plants, refineries, and other perilous applications. Fire-safe valves, the first line of defense in containing a fire, were introduced some 25 years ago, with fire-safe actuators following soon afterwards. Little attention has been given, however, to designing and selecting the other piping components such as flanges, gaskets, bolting, and fittings to ensure their integrity in a fire. Just like in an electric circuit where, if a single component in series fails, the flow of electricity stops;likewise, the failure of a single piping component could result in a fire of catastrophic proportions. This paper discusses the availability of critical fire-safe components for Navy shipboard piping systems and provides some simple solutions which, if implemented, could prevent such a disaster. discussion is provided on how a fire starts and how it reaches catastrophic proportions, the definitions of survivability and fire-safe components, materials of construction, component design, fire-safe valves and actuators, gaskets, pipe flanges, flange bolting, pipe fittings and unions, brazing and welding, insulation, composite piping materials, and other related subjects. details are also provided on 78 fires that have occurred on Navy surface ships in the last ten years and their causes.

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ArCHITECTUrE ANd NETWOrKING ISSUES IN SATELLITE SYSTEMS FOr PErSONAL COMMUNICATIONS

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INTErNATIONAL JOUrNAL OF SATELLITE COMMUNICATIONS 1994年第1期12卷 33-44页

作者： ANANASSO, F CArOSI, M Received the Electronics and Electrical Communications Degree from the University of Rome in 1973 after which he joined Selenia S.p.A (Rome) as a microwave designer in the Development Laboratory. He was involved in several military and civilian projects concerning microwave subsystems for Radar Avionics and Satellite Communications equipment. In 1981 he joined Telespazio S.p.A. (Rome) as Section Chief in the Space and Advanced Programs Division with responsibilities related to satellite payload and digital transmission channel design. In 1987 he was appointed Associate Professor of Digital Signal Processing at the University of Rome Tor Vergata Electronics Engineering Department. In 1990 he again joined Telespazio where he is now Director of the Advanced Studies and Experimentations Division. He has performed a number of studies for National and International Organizations including ESA EUTELSAT INMARSAT and INTELSAT is author of a Radio Systems book a Chapter (‘Digital transmission channel’) of the ‘Satellite Communication System Design’ book by Plenum Publishing (1993) and over 80 technical papers on communication systems and technology. Received the Electronics and Electrical Communications Degree from the University ‘La Sapienza’ of Rome Italy in 1987. From 1987 to 1990 he worked as a Research Engineer in the INFOCOM department of the University ‘La Sapienza’ of Rome carrying out research on design and performance evaluation of multiple access protocols particularly in the metropolitan area network and in the satellite fields. Since 1990 he has been working in the System Studies and Payload group of Telespazio S.p.A. Rome Italy. He is currently involved in projects sponsored by the European Space Agency and by INMARSAT for communications systems via satellite for mobiles both at study and R&D level. Mr Carosi is a member of the IEEE Communication Society.

The paper expands on some specific aspects of personal communications via satellite, often-although not necessarily-envisaging extensive use of 'small' satellites, using orbits not necessarily coinciding with the geostationary one (36,000 km), but rather at 1000-11,000 km altitude. One key point to be borne in mind is the issue of internetworking between satellite and terrestrial systems. Network integration should be carefully implemented in order to comply with ITU future public land mobile telecommunication systems (FPLMTS) requirements, also accepted in the European Telecommunication Standards Institute (ETSI) universal mobile telecommunication systems (UMTS). In addition to some insight into the technology of small satellites and associated orbits, architectures and networking aspects of most relevant systems providing personal communication services (PCS) are addressed in some detail, and potential applications highlighted. Frequency spectrum allocation is addressed in the light of the 1992 World Administrative radio Conference (WArC-92), taking into account also multiple access problems and regulatory issues such as Federal Communications Commission (FCC) licensing and spectrum sharing debates. Some remarks on critical technologies and cost conclude the paper.

关键词： PErSONAL COMMUNICATIONS SMALL SATELLITES NETWOrKING FrEQUENCY SPECTrUM

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PErFOrMANCE OF A PrIOrITIZEd ON-BOArd BASEBANd SWITCH FOr A MULTISErVICE MULTIBEAM SATELLITE

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INTErNATIONAL JOUrNAL OF SATELLITE COMMUNICATIONS 1994年第3期12卷 283-297页

作者： BOHM, S ELHAKEEM, AK HACHICHA, M Department of Electrical and Computer Engineering Concordia University 1455 De Maisonneuve Blvd. West Montreal H3A 1M8 Canada Was born in Montreal Canada on 14 September 1966. He received the B. Eng. degree in electrical engineering from Concordia University Montreal Canada in 1989. He is at present completing the M.A.Sc. degree in electrical engineering at Concordia University. (S'75–S'79–M'79–SM'86) received the Ph.D. degree from Southern Methodist University Dallas TX in 1979. He spent the next two years working as a Visiting Professor in Egypt after which he moved to Ottawa Canada in 1982. He assumed teaching and research positions in Carleton and Manitoba Univerities and later moved to Concordia University Montreal Canada in 1983 where he is now a Professor in the Electrical and Computer Engineering Department. He has published numerous papers in IEEE and international journals in the areas of spread spectrum and networking. He is a well-known expert in these areas and serves as a consultant to many companies. His current research interests include wide-band metropolitan networks switching architectures and performance of on-board multibeam satellites acquisitionless CDMA networks code distribution and orthogonalization of CDMA signals responsive congestion control for ATM-based networks ARQ techniques and investigation of the novel SUGAR CDMA systems in fading channels. Dr. Elhakeem is a Senior Member of the Canadian Electrical Engineering Society and Armed Forces Association. He has chaired numerous technical sessions in IEEE Conferences was the Technical Program Chairman for IEEE Montech 1986 Montreal Canada. Dr. Elhakeem is the key guest editor of theIEEE Journal of Selected Areas in Communicationsfor the May June issues 1993 covering CDMA networks. Advanced Technology & Networks VISTAR Telecommunications Inc. Ottawa Ontario K1G 3J4 Canada An Associate Director of Advanced Technology & Networks Group VISTAR Telecommunications Inc. Ottawa Canada. He is also an Adjunct Pr

In this paper, we study the performance of a prioritized on-board baseband switch in conjunction with a multibeam satellite handling integrated services. The services considered for the analysis include voice, video, file transfer and interactive data. The prioritized switch uses both input and output buffering, switch speed-up as well as a two-phase head-of-line resolution algorithm, in order to reduce the buffer loss while maintaining acceptable user delays. The minimum required buffer capacity and switch speed-up for each service in a prioritized environment are found under uniform traffic conditions. It is shown that under uniform traffic conditions, only minimal buffering and switch speed-up are needed even for the lowest priority users. The performance dependence on the switch size is also substantially reduced with head of line resolution and buffering even in a prioritized environment.

关键词： SWITCH ON-BOArd BASEBANd MULTIBEAM PrIOrITIZEd HEAd-OF-LINE UNIFOrM LOAd SPEEd-UP

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